Many individuals judge the quality of their exercise session from the amount of pain they experience afterwards. These individuals are convinced by the old adage No Pain No Gain. Research on Delayed Onset Muscle Soreness (DOMS) has demonstrated that here may in fact be some truth to this phrase.

Recall in a previous article presented on this website dealing with Delayed Onset Muscle Soreness, we discussed the high probability that muscular pain after exercise results from actual muscle damage. This damage is viewed by the immune system as would any other injury and as a result, an inflammatory response is initiated to start the healing process. Several substances and chemicals are released during an inflammatory response and are thought to enhance the sensation of pain by excessively stimulating the nerve endings in the damaged tissue. So since pain is associated with muscle damage, in some cases it may be a fair indicator of a good workout or running session. The repair and healing of damaged muscle allows for hypertrophy or enlargement of the muscle fiber by the addition of myofibrils, thus increasing the cross sectional area.

Excessive muscle pain that continues for more than several days or continuously however is not desirable, as this is often an indicator of athlete overtraining or over-reaching. It must be stressed that if pain is experienced, it should be a good pain that is, not originating in the joints and should resolve within a couple of days. As exercise becomes more regular and the exerciser more accustomed to it, it will be noticed however that it becomes increasingly harder to elicit the same painful muscle response. The reason for this is unclear at this time but it is suggested that an exercise session that causes DOMS has a protective effect on subsequent exercise - lasting several weeks. Again it is unclear the exact mechanisms behind this protective effect.

In conclusion then, a regular exerciser should not place a high value on the No Pain No Gain evaluation of their workout, as their muscles will be less susceptible to the effects of DOMS. Rather it is suggested to concentrate on other factors such as strict technique and exercise variety so as to avoid undue stress on the joints and overtraining of single muscle groups.